How the Ulstein design team meets the subsea vessel demand
The positive trends in the offshore energy market led Ulstein to develop the ULSTEIN SX232, a new subsea vessel that combines innovation, versatility, and emission reduction. It serves the offshore wind market for floating and fixed installations as for offshore oil & gas.
Three core principles
The ULSTEIN SX232 is based on three core principles that make it stand out from the competition:
- an optimized hull design based on the ULSTEIN TWIN X-STERN,
- a smart power and propulsion system developed to minimize energy consumption during DP operations and
- an integrated energy recovery system utilizing all the waste heat in the machinery systems (cooling water and exhaust).
These features enable the ULSTEIN SX232 to reduce emissions and operational costs while enhancing performance, safety, and comfort.
Designing for future needs
The design has been developed to include versatile fuel options and a battery energy storage system for peak shaving and spinning reserve purposes has been implemented.
The vessel’s forward section accommodates 130 people and includes two remotely operated vehicle (ROV) hangars. A moonpool is positioned at the rear of the accommodation block, complemented by an expansive flat deck spanning over 2,000 m². This flat deck design enhances the vessel’s adaptability, allowing multiple operational setups to suit diverse maritime tasks.
The basic platform has been configured with a 250-tonne offshore crane; however, the platform can also support a larger crane of 400 tonnes.
With the upgraded crane capacity, the vessel could support the installation of suction anchors, which are common for floating offshore energy.
An alternative use of the ULSTEIN SX232 platform is for inter-array cable laying operations.
The designer's illustration of 6 x 20 m suction anchors on deck.- An alternative use of the ULSTEIN SX232 platform is for inter-array cable laying operations. This is a potential configuration with a 5,000 tonnes carrousel on deck and two cable-lay spreads. The vessel is equipped with an additional 3,500 tonnes carousel under deck, providing a total cable capacity of 8,500 tonnes.
- For floating wind, inter array installations need to be performed with a different configuration. Here a J-lay system will be required. In this figure, the vessel has a J-lay configuration with the tower over the stern.
- This floating wind setup illustrates a J-lay setup through the moonpool.
- This is an example of a J-lay configuration with the tower over the side.
Ulstein's subsea portfolio
The ULSTEIN SX232 joins Ulstein’s portfolio of subsea vessels.
Together with the ULSTEIN SX239, it is the first subsea vessel to integrate the ULSTEIN TWIN X-STERN.
The ULSTEIN TWIN X-STERN has been designed for walk-to-work operations in the offshore energy market. Ten TWIN X-STERN vessels are currently being built, with the first to enter operations in 2024.
See our subsea portfolio and references
Our subsea portfolio includes flexible designs for Offshore Construction, Well Intervention, Inspection/Maintenance/Repair (IMR), Subsea Umbilicals, Risers and Flowlines (SURF) and rock installation vessels.
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